John Sheppard and Rodney McKay enter the Atlantis control room, when Chuck informs them that a starship has just appeared out of nowhere above M35-117. McKay identifies the IFF signal as the Daedalus, which they find odd, as the Daedalus has actually almost completed a return journey to Earth, which Stargate Command later confirms. They also find no life signs on board either. Sheppard sends his team to the ship via Puddle Jumper. Upon arriving, McKay notices that the systems are nearly dead, as the ship is barely giving off any energy readings. They noticed signs of battle, as the ship has visible burn marks from weapons fire. When they arrive, McKay notices another energy reading, not familiar to the Daedalus.
McKay works to restore power, but discovers that vital systems, including weapons and shields are barely online, not to mention that Subspace communications and Hyperdrives are damaged beyond repair. Teyla finds a recording in the computer -- the final entry of the ship's log. It is Colonel Sobel, apparently the commander of the Daedalus, who reports that equipment and supplies have been transported down to the planet's surface, where she and her crew hope to survive long enough to be found and rescued. Sobel plans to soon join them in an F-302 fighter. The crew's predicament and the reason for their evacuation, however, is not the first question that Sheppard and the team have. The first question is ... Who is Sobel?
Soon, the unfamiliar energy reading starts spiking from the centre of the ship. Sheppard believes that they should leave. However, just as they leave the bridge, the ship flashes out of nowhere. After the energy levels drop, they contact Atlantis, only there is no response. Atlantis can't get a response either. According to Zelenka, the ship has disappeared.
Meanwhile, the team discovers that Atlantis has disappeared; the team are on the same planet, but there is no sign of the base, just ocean. McKay notices that the energy readings are very similar to the one where a McKay from a parallel universe visited Atlantis two years ago, which leads him to believe that that Daedalus is from an alternate reality. The team rush to the location of the energy reading and find an Alternate reality drive, which was created by McKay in another universe. When they find it, they found a duplicate of their team, dead. The alternate team also came to investigate the ship, weeks or months ago, but couldn't find a way out. They eventually ran out of supplies and starved to death. Soon the drive recharges and jumps to the next universe.
Upon reaching a second parallel universe, an unidentified alien vessel is attacking a parallel Atlantis. The team disables the ship by taking out its weapons with three shots from the Asgard weapons but soon come under attack from alien fighters, who quickly gain the advantage which quickly depletes what little shield they have left. Ronon and Sheppard use the ship's railguns to defend the ship. But in the process, one of the fighters is damaged and crashes into the ship. McKay manages to jump the ship to the next reality, by sending all of the ship's power to the alternate reality drive, causing them to jump sooner but over-taxing it, which would eventually cause the ship to be set to burn out in just a handful of jumps. However, the next universe they end up in, they orbit over a red giant, the same star that should turn into a red giant 48,000 years from now is happening sooner in that reality. McKay desperately attempts to transfer all available power to the jump drive before the hull temperature gets too critical.
Ronon hears a noise from a corridor and comes to investigate. He opens a door to find a mysterious alien, who was one of the survivors from the crashed fighter. The alien proved to be more of a match for Ronon. However, he manages to use his free hand to fire his weapon in the air, which alerts Sheppard to his position and takes down the alien, but requires a full magazine from his P-90 before finally taking him down. Soon however, they are under fire from two more aliens. Sheppard and Ronon take cover and a firefight ensues. Meanwhile, McKay tells Teyla to drop whatever shields they have left so the power could be transferred to the drive. It worked and the drive charges up before the hull completely deteriorate and they jump to a fourth parallel universe. Sheppard and Ronon use the flash to their advantage, by getting out of hiding and killing the two aliens.
They discover that M35-117 is nothing but a field of asteroids. McKay figures out how to put the drive in reverse and return to their own reality by going backwards through the realities. To deal with the Sun, he uses the maneuvering thrusters to move the ship higher so they jump into a higher orbit and works on fixing the sublight engines to escape the aliens from the second parallel universe.
They eventually jump back to the reality with the aliens and come under attack again. McKay gets the engines going and the ship runs for it while Sheppard and Ronon use the railguns to hold off the enemy fighters, gaining on them from behind. Soon after the fighters caught up and took down the The engines for good, the Daedalus is outnumbered with no shields near destruction, when the Atlantis of that reality launches a F-302 attack, led by an alternate Sheppard to help. Together the Daedalus and the 302s defeat the alien fighters, including one that was about to collide with the bridge. After both Sheppards congratulated each other on their work, the ship jumps back to the first reality they jumped to. They plan to go to the Jumper the second the ship returns to the right universe.
However, on the way to the hanger bay, they come under attack from the remaining alien, who shoots McKay on the right shoulder. Ronon, Sheppard and Teyla manage to take down the alien. But just as he impacts the floor, he activates an explosive device. Sheppard and Ronon leave the corridor and closes off the section before detonating the device. However, the explosion blows a hole in the hull that cuts them off from the hanger bay.
When they eventually jump back to the correct reality, Major Lorne and Doctor Zelenka pick up the Daedalus again on sensors. They board a Jumper and approach the ship. However, Zelenka detects an energy spike and see the ship flash out of existence. They did however, pick up four lifesigns ahead, who are the team in space suits.
After recovering in the infirmary, McKay plans to design his own alternate reality drive, which Sheppard quickly opposes, despite the fact McKay could remove the flaws. Teyla comes to the infirmary with Torren, who lets him hold the baby for a minute.
Alternate reality; Alternate reality drive; Apollo; Asgard plasma beam weapon; Asuran; Atlantis; Battle of M35-117; Daedalus; Earth; F-302; Fighter (The Daedalus Variations); Kevin Marks; M1911A1 pistol; M35-117; McKay and Mrs. Miller; P-90; Radiation; Railgun; Red giant; Shield; Ship (The Daedalus Variations); Sobel; Stargate Command; Subspace capacitor; Subspace communication; Thermal grenade; Torren John Emmagan; Traveler energy pistol; Unknown Alien; Unknown Alien weapon
- Jennifer Keller and Richard Woolsey do not appear in the episode.
- This is the third episode, after Sateda and Phantoms, where McKay gets shot.
- Sheppard has again refered to Ronon as Chewie, after he went mad at the controls, which Chewbacca did during some of the space battles in the Star Wars films.
- On the second parallel universe, the alternate Sheppard told our Sheppard that their Daedalus was destroyed on the attack of the Replicators in 2006. This could mean that some of the events played out on that reality happens sooner than in this reality, as in 2006, our Expedition just discovered the Replicators. On that note, it is possible that the unknown aliens may appear later in our reality later in the series.
- The chart behind the alternate Daedalus' captain's chair is set at a different angle (at about 90 degrees) and is orange, instead of green, which is the case of our Daedalus. This was simply a means to differentiate the alternate ship from the Daedelus from this reality, as confirmed by the episode's writer Alan McCullough.
- The script for "The Daedalus Variations", written by Alan McCullough was handed in on February 11, 2008, with further discussion regarding aspects of the episode on February 12.
- Joseph Mallozzi's February 15th blog shows an image of an alien thermal grenade for use in this episode. Mallozzi's March 8th blog shows a blast door that is to be shown many times in the episode.
- The actor playing Colonel Sobel was cast on March 10, 2008.
- On Joseph Mallozzi's blog, the writer for the episode said that one of the alternate realities that were discussed was a version where the Ancients won the war against the Wraith but it was decided that this would detract from the story and it never made it into production.
1. The Daedalus Variations on Gateworld.net, retrieved 2008.